Work Processes and Working ConditionsThe benefits of working during pregnancy include both the income and the enjoyment of the work itself. However, pregnancy places an extra burden on a woman physiologically, at first with tiredness, and nausea, and later in pregnancy through the extra physical weight. Women who work during pregnancy do not have a clearly better or worse pregnancy outcome on average than those who do not work. However, some factors - long hours, standing or a heavy workload - are associated with an increased risk of premature delivery or low birth weight.

Chemical AgentsChemical exposure is undoubtedly the most important reproductive hazard for employees. Once chemicals enter the mother's body, they may often enter the body of the foetus through the placenta. The small size and weight of the foetus, along with the foetal liver's limited capacity to detoxify these substances, increases the potential for liver damage.

Physical AgentsPhysical hazards may include excessive noise, vibration, extremes of temperature, ionizing (Ionizing radiation comes from radioactive materials, e.g. x-ray tubes, ) and non-ionising radiation (Lasers, ultra-violet, infra-red, microwave) materials handling, movements and postures, traveling, mental and physical fatigue and other physical burdens connected with the activities of new or expectant mothers. Ionising radiation is the only physical hazard that is a known reproductive hazard. At doses around 100 times the annual dose limits for persons occupationally exposed, it profoundly affects reproductive function in men and women as well as the developing embryo/ foetus.

Biological AgentsBiological agents (such as viruses, fungi, spores, and bacteria) may impair fertility in men and women or cause adverse effects during pregnancy, despite advances in diagnostic techniques, vaccines, and antibiotics. Several infections during pregnancy, including rubella, chicken pox, hepatitis B and toxoplasmosis have been associated with birth defects and miscarriage risks. Women working in hospitals, laboratories, with children or with animals may be at higher risk if they become pregnant.

Return to workThe timing of return to work after childbirth depends on a number of medical, social and economic factors. Should a woman wish to return to work within the first 6 weeks after the birth of her child then this should be permitted only after certification of fitness from the attending medical practitioner.

Breast FeedingEmployers who have nursing mothers working in environments in which they are exposed to substances that could be excreted in breast milk should assess whether exposure would be sufficient to produce significant concentrations in the breast milk of employees who are breastfeeding. Key substances of concern are selected organic solvents, metals and pesticides.

Employees should be notified of the potential for accumulation of chemical contaminants in breast milk. Breastfeeding is widely regarded as the best nutrition and as a major preventive health measure for infants through their first birthday.

Men's issuesIt is not well known, however, that a man's exposure to substances in the workplace can affect his ability to have healthy children.

Reproductive safety is not solely a women's issue. Reproductive hazards in the workplace may affect men or women. Research on reproductive hazards in the workplace has traditionally focused on female workers, but there is growing evidence of occupational reproductive toxicity in the male, varying all the way from loss of libido to loss of potency, disturbance in ejaculation, and varying degrees of abnormalities in the sperm. Among the compounds known to affect adversely male reproduction are vinyl chloride, organic lead, inorganic mercury, chlordecone, chloroprene, and dibromochloropropane.

The lead maternity carer will need information about the pregnant employee's job and working conditions to assist the woman to make informed choices about the suitability of her employment during pregnancy, and about how long she should continue to work.